XML to DDL的项目关键：与数据库同步

DROP TABLE students;
CREATE TABLE students (
id integer,
student_name varchar(80),
CONSTRAINT pk_students PRIMARY KEY (id));
COMMENT ON TABLE students IS 'List of students with their full names';
COMMENT ON COLUMN students.id IS 'Primary key for the table';
COMMENT ON COLUMN students.student_name IS 'The full name of the student';

<schema>
<table name="students" fullname="List of Students"
desc="List of students">
　 <columns>
<column name="id" fullname="Primary Key" type="integer" key="1"
desc="Primary key for the table"/>
<column name="student_name" fullname="Student Name"
type="varchar" size="100"
desc="The full name of the student"/>
<column name="email" fullname="Electronic mail address"
type="varchar" size="100"
desc="The primary email for the student"/>
</columns>
</table>
</schema>

ALTER TABLE students ALTER student_name TYPE varchar(80);
ALTER TABLE students DROP email;
COMMENT ON TABLE students IS 'List of students with their full names';